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Magnetic nanoparticles as building blocks for nanomaterials

Nanoparticles can be considered as building blocks for artificial super-structures. One prominent route is to employ the self-organization of particles into regular arrangements, so called nanoparticle supercrystals. Such arrangements can show various magnetic collective properties e.g. superspin glass or superferromagnetic behavior. In most cases the magnetic dipole-dipole interaction between the particles is reponsible for these properties.

In the case of isolated nanoparticles, often superparamagnetism is observed. We have recently shown that it is also possible to switch between superspin glass and superferromagnetic behavior by applying the magnetic field in different directions.

If the magnetic properties of the nanoparticles are combined with ferroelectric properties in a composite system, magneto-electric properties of the composite can emerge (see figure). E.g. ferrimagnetic-ferroelectric composites based on magnetic nanoparticles are promising novel candidates for spintronic devices.

A significant magneto-electric coupling effectOn the left hand side the various fabricated systems are depicted and at the right hand side the corresponding magnetic moment vs. temperature FC/FW curves. For the third system, i.e. particles enbedded in an Au layer on top of the BTO substrate a significant magneto-electric coupling effect is observed.
Copyright: Forschungszentrum Jülich

References:

  1. B. Bedanta, O. Petracic, and W. Kleemann, Supermagnetism, Handbook of Magnetic Materials, Ed. K.H.J. Buschow, Volume 23 (2015) 
  2. L. -M. Wang, A. Qdemat, O. Petracic, E. Kentzinger, U. Rücker, F. Zheng, P. -H. Lu, X. -K. Wei, R. E. Dunin-Borkowski, and Th. Brückel, Manipulation of dipolar magnetism in low-dimensional iron oxide nanoparticle assemblies, Phys. Chem. Chem. Phys. 21, 6171 (2019) 
  3. L. -M. Wang, O. Petracic, E. Kentzinger, U. Rücker, and Th. Brückel, Strain and electric-field control of magnetism in supercrystalline iron oxide nanoparticle–BaTiO3 composites, Nanoscale 9, 12957 (2017)

Contact: 


Oleg Petracic 
Phone: +49 2461 61-4036 
email: o.petracic@fz-juelich.de

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